I'm pretty slow with the electronics that go along with performance. However, what I've found is that where I face makes all the difference in the world.
Even more difference is created by where the other instruments are and are facing. I have played with a bass, a violin, drums, and so forth, and managed to avoid the kind of feedback I used to experience. I might just be lucky, and my understanding might be seriously flawed. Just thought I've chime in....